Prevent AccessibilityInteractionClient.getWindows()

returns partially cached windows list.

It could happen that AccessibilityWindowInfo cache is
cleared. And after that calling
AccessibilityInteractionClient.getWindow(windowId)
would add that window to cache. And while cache is
not empty after that AccessibilityInteractionClient
returns its content on getWindows() request even
if it does not contain all windows.

Change-Id: I70dc96d50e3368285fd482a98769a93ae2c15f22

2 files changed, 36 insertions, 11 deletions

diff --git a/core/java/android/view/accessibility/AccessibilityCache.java b/core/java/android/view/accessibility/AccessibilityCache.java
index d0dde00746bd..1da305f09f54 100644
--- a/core/java/android/view/accessibility/AccessibilityCache.java
+++ b/core/java/android/view/accessibility/AccessibilityCache.java
@@ -43,6 +43,8 @@ final class AccessibilityCache {
     private long mAccessibilityFocus = AccessibilityNodeInfo.UNDEFINED_ITEM_ID;
     private long mInputFocus = AccessibilityNodeInfo.UNDEFINED_ITEM_ID;
 
+    private boolean mIsAllWindowsCached;
+
     private final SparseArray<AccessibilityWindowInfo> mWindowCache =
             new SparseArray<>();
 
@@ -52,6 +54,24 @@ final class AccessibilityCache {
     private final SparseArray<AccessibilityWindowInfo> mTempWindowArray =
             new SparseArray<>();
 
+    public void setWindows(List<AccessibilityWindowInfo> windows) {
+        synchronized (mLock) {
+            if (DEBUG) {
+                Log.i(LOG_TAG, "Set windows");
+            }
+            clearWindowCache();
+            if (windows == null) {
+                return;
+            }
+            final int windowCount = windows.size();
+            for (int i = 0; i < windowCount; i++) {
+                final AccessibilityWindowInfo window = windows.get(i);
+                addWindow(window);
+            }
+            mIsAllWindowsCached = true;
+        }
+    }
+
     public void addWindow(AccessibilityWindowInfo window) {
         synchronized (mLock) {
             if (DEBUG) {
@@ -186,6 +206,10 @@ final class AccessibilityCache {
 
     public List<AccessibilityWindowInfo> getWindows() {
         synchronized (mLock) {
+            if (!mIsAllWindowsCached) {
+                return null;
+            }
+
             final int windowCount = mWindowCache.size();
             if (windowCount > 0) {
                 // Careful to return the windows in a decreasing layer order.
@@ -280,12 +304,7 @@ final class AccessibilityCache {
             if (DEBUG) {
                 Log.i(LOG_TAG, "clear()");
             }
-            final int windowCount = mWindowCache.size();
-            for (int i = windowCount - 1; i >= 0; i--) {
-                AccessibilityWindowInfo window = mWindowCache.valueAt(i);
-                window.recycle();
-                mWindowCache.removeAt(i);
-            }
+            clearWindowCache();
             final int nodesForWindowCount = mNodeCache.size();
             for (int i = 0; i < nodesForWindowCount; i++) {
                 final int windowId = mNodeCache.keyAt(i);
@@ -297,6 +316,16 @@ final class AccessibilityCache {
         }
     }
 
+    private void clearWindowCache() {
+        final int windowCount = mWindowCache.size();
+        for (int i = windowCount - 1; i >= 0; i--) {
+            AccessibilityWindowInfo window = mWindowCache.valueAt(i);
+            window.recycle();
+            mWindowCache.removeAt(i);
+        }
+        mIsAllWindowsCached = false;
+    }
+
     private void clearNodesForWindowLocked(int windowId) {
         if (DEBUG) {
             Log.i(LOG_TAG, "clearNodesForWindowLocked(" + windowId + ")");
diff --git a/core/java/android/view/accessibility/AccessibilityInteractionClient.java b/core/java/android/view/accessibility/AccessibilityInteractionClient.java
index b49cbc6245ba..1406fbd9d074 100644
--- a/core/java/android/view/accessibility/AccessibilityInteractionClient.java
+++ b/core/java/android/view/accessibility/AccessibilityInteractionClient.java
@@ -228,11 +228,7 @@ public final class AccessibilityInteractionClient
                 windows = connection.getWindows();
                 Binder.restoreCallingIdentity(identityToken);
                 if (windows != null) {
-                    final int windowCount = windows.size();
-                    for (int i = 0; i < windowCount; i++) {
-                        AccessibilityWindowInfo window = windows.get(i);
-                        sAccessibilityCache.addWindow(window);
-                    }
+                    sAccessibilityCache.setWindows(windows);
                     return windows;
                 }
             } else {